Measuring brain perfusion with intravoxel incoherent motion (IVIM): Initial clinical experience.

PURPOSE: To evaluate the feasibility of intravoxel incoherent motion (IVIM) perfusion measurements in the brain with currently available imaging systems. MATERIALS AND METHODS: We acquired high in-plane resolution (1.2 × 1.2 mm(2) ) diffusion-weighted images with 16 different values of b ranging from 0 to 900 s/mm(2) , in three orthogonal directions, on 3T systems with a 32-multichannel receiver head coil. IVIM perfusion maps were extracted by fitting a double exponential model of signal amplitude decay. Regions of interest were drawn in pathological and control regions, where IVIM perfusion parameters were compared to the corresponding dynamic susceptibility contrast (DSC) parameters. RESULTS: Hyperperfusion was found in the nonnecrotic or cystic part of two histologically proven glioblastoma multiforme and in two histologically proven glioma WHO grade III, as well as in a brain metastasis of lung adenocarcinoma, in a large meningioma, and in a case of ictal hyperperfusion. A monoexponential decay was found in a territory of acute ischemia, as well as in the necrotic part of a glioblastoma. The IVIM perfusion fraction f correlated well with DSC CBV. CONCLUSION: Our initial report suggests that high-resolution brain perfusion imaging is feasible with IVIM in the current clinical setting. J. Magn. Reson. Imaging 2014;39:624-632. © 2013 Wiley Periodicals, Inc.

Measuring the diurnal pattern of leaf hyponasty and growth in Arabidopsis - a novel phenotyping approach using laser scanning

Plants forming a rosette during their juvenile growth phase, such as Arabidopsis thaliana (L.) Heynh., are able to adjust the size, position and orientation of their leaves. These growth responses are under the control of the plants circadian clock and follow a characteristic diurnal rhythm. For instance, increased leaf elongation and hyponasty - defined here as the increase in leaf elevation angle - can be observed when plants are shaded. Shading can either be caused by a decrease in the fluence rate of photosynthetically active radiation (direct shade) or a decrease in the fluence rate of red compared with far-red radiation (neighbour detection). In this paper we report on a phenotyping approach based on laser scanning to measure the diurnal pattern of leaf hyponasty and increase in rosette size. In short days, leaves showed constitutively increased leaf elevation angles compared with long days, but the overall diurnal pattern and the magnitude of up and downward leaf movement was independent of daylength. Shade treatment led to elevated leaf angles during the first day of application, but did not affect the magnitude of up and downward leaf movement in the following day. Using our phenotyping device, individual plants can be non-invasively monitored during several days under different light conditions. Hence, it represents a proper tool to phenotype light- and circadian clock-mediated growth responses in order to better understand the underlying regulatory genetic network.

Measuring potentially avoidable hospital readmissions.

The objectives of this study were to develop a computerized method to screen for potentially avoidable hospital readmissions using routinely collected data and a prediction model to adjust rates for case mix. We studied hospital information system data of a random sample of 3,474 inpatients discharged alive in 1997 from a university hospital and medical records of those (1,115) readmitted within 1 year. The gold standard was set on the basis of the hospital data and medical records: all readmissions were classified as foreseen readmissions, unforeseen readmissions for a new affection, or unforeseen readmissions for a previously known affection. The latter category was submitted to a systematic medical record review to identify the main cause of readmission. Potentially avoidable readmissions were defined as a subgroup of unforeseen readmissions for a previously known affection occurring within an appropriate interval, set to maximize the chance of detecting avoidable readmissions. The computerized screening algorithm was strictly based on routine statistics: diagnosis and procedures coding and admission mode. The prediction was based on a Poisson regression model. There were 454 (13.1%) unforeseen readmissions for a previously known affection within 1 year. Fifty-nine readmissions (1.7%) were judged avoidable, most of them occurring within 1 month, which was the interval used to define potentially avoidable readmissions (n = 174, 5.0%). The intra-sample sensitivity and specificity of the screening algorithm both reached approximately 96%. Higher risk for potentially avoidable readmission was associated with previous hospitalizations, high comorbidity index, and long length of stay; lower risk was associated with surgery and delivery. The model offers satisfactory predictive performance and a good medical plausibility. The proposed measure could be used as an indicator of inpatient care outcome. However, the instrument should be validated using other sets of data from various hospitals.

Long-term impacts of forest harvesting related soil disturbance on log product yields and economic potential in a New Zealand forest

Abstract

Alkali Content of Fly Ash – Measuring and Testing Strategies for Compliance, TR-628, 2015

Sodium and potassium are the common alkalis present in fly ash. Excessive amounts of fly ash alkalis can cause efflorescence problems in concrete products and raise concern about the effectiveness of the fly ash to mitigate alkali-silica reaction (ASR). The available alkali test, which is commonly used to measure fly ash alkali, takes approximately 35 days for execution and reporting. Hence, in many instances the fly ash has already been incorporated into concrete before the test results are available. This complicates the job of the fly ash marketing agencies and it leads to disputes with fly ash users who often are concerned with accepting projects that contain materials that fail to meet specification limits. The research project consisted of a lab study and a field study. The lab study focused on the available alkali test and how fly ash alkali content impacts common performance tests (mortar-bar expansion tests). Twenty-one fly ash samples were evaluated during the testing. The field study focused on the inspection and testing of selected, well documented pavement sites that contained moderately reactive fine aggregate and high-alkali fly ash. A total of nine pavement sites were evaluated. Two of the sites were control sites that did not contain fly ash. The results of the lab study indicated that the available alkali test is prone to experimental errors that cause poor agreement between testing labs. A strong (linear) relationship was observed between available alkali content and total alkali content of Class C fly ash. This relationship can be used to provide a quicker, more precise method of estimating the available alkali content. The results of the field study failed to link the use of high-alkali fly ash with the occurrence of ASR in the various concrete sites. Petrographic examination of the pavement cores indicated that Wayland sand is an ASR-sensitive aggregate. This was in good agreement with Iowa DOT field service records. It was recommended that preventative measures should be used when this source of sand is used in concrete mixtures.

Field Evaluation of Electro-Reflective Measuring Apparatus (ERMA), MLR-81-01, 1981

The Electro-Reflective Measuring Apparatus (ERMA) was developed by the Minnesota Department of Highways in 1974 to measure the retro-reflective characteristics of pavement marking materials. Minnesota researchers recommended that due to the increased cost of pavement marking materials and reduced availability of these materials, ERMA can and should be used as a maintenance management tool to determine when painting is necessary rather than according to a fixed time schedule. The Iowa DOT Office of Materials built an ERMA device patterned after Minnesota's design in 1976. Subsequent efforts to calibrate and correlate this ERMA device to District Paint Foremen ratings proved unsuccessful, and ERMA modification or abandonment was recommended in 1979. Lyman Moothart, Materials Lab. Tech. 4, modified the ERMA device in 1980 and correlation attempts to District Paint Foremen ratings conducted in November 1980 have been moderately successful. A Paint/No Paint ERMA value has been established which will identify about 90% of the painting needs but will also include about 40% of the marking lines not needing repainting. The Office of Maintenance should establish a trial ERMA program to study the accuracy and potential cost savings of using ERMA to identify pavement marking needs.

Predicting the physicochemical profile of diastereoisomeric histidine-containing dipeptides by property space analysis.

OBJECTIVES: This study aimed at measuring the lipophilicity and ionization constants of diastereoisomeric dipeptides, interpreting them in terms of conformational behavior, and developing statistical models to predict them. METHODS: A series of 20 dipeptides of general structure NH(2) -L-X-(L or D)-His-OMe was designed and synthetized. Their experimental ionization constants (pK(1) , pK(2) and pK(3) ) and lipophilicity parameters (log P(N) and log D(7.4) ) were measured by potentiometry. Molecular modeling in three media (vacuum, water, and chloroform) was used to explore and sample their conformational space, and for each stored conformer to calculate their radius of gyration, virtual log P (preferably written as log P(MLP) , meaning obtained by the molecular lipophilicity potential (MLP) method) and polar surface area (PSA). Means and ranges were calculated for these properties, as was their sensitivity (i.e., the ratio between property range and number of rotatable bonds). RESULTS: Marked differences between diastereoisomers were seen in their experimental ionization constants and lipophilicity parameters. These differences are explained by molecular flexibility, configuration-dependent differences in intramolecular interactions, and accessibility of functional groups. Multiple linear equations correlated experimental lipophilicity parameters and ionization constants with PSA range and other calculated parameters. CONCLUSION: This study documents the differences in lipophilicity and ionization constants between diastereoisomeric dipeptides. Such configuration-dependent differences are shown to depend markedly on differences in conformational behavior and to be amenable to multiple linear regression. Chirality 24:566-576, 2012. © 2012 Wiley Periodicals, Inc.

Examination of Curing Criteria for Cold In-Place Recycling Phase 2: Measuring Temperature, Moisture, Deflection and Distress from CIR Test Section, TR-590, 2009

The previous research performed laboratory experiments to measure the impacts of the curing on the indirect tensile strength of both CIR-foam and CIR-emulsion mixtures. However, a fundamental question was raised during the previous research regarding a relationship between the field moisture content and the laboratory moisture content. Therefore, during this research, both temperature and moisture conditions were measured in the field by embedding the sensors at a midpoint and a bottom of the CIR layer. The main objectives of the research are to: (1) measure the moisture levels throughout a CIR layer and (2) develop a moisture loss index to determine the optimum curing time of CIR layer before HMA overlay. To develop a set of moisture loss indices, the moisture contents and temperatures of CIR-foam and CIR-emulsion layers were monitored for five months. Based on the limited field experiment, the following conclusions are derived: 1. The moisture content of the CIR layer can be monitored accurately using the capacitance type moisture sensor. 2. The moisture loss index for CIR layers is a viable tool in determining the optimum timing for an overlay without measuring actual moisture contents. 3. The modulus back-calculated based on the deflection measured by FWD seemed to be in a good agreement with the stiffness measured by geo-gauge. 4. The geo-gauge should be considered for measuring the stiffness of CIR layer that can be used to determine the timing of an overlay. 5. The stiffness of CIR-foam layer increased as a curing time increased and it seemed to be more influenced by a temperature than moisture content. The developed sets of moisture loss indices based on the field measurements will help pavement engineers determine an optimum timing of an overlay without continually measuring moisture conditions in the field using a nuclear gauge.

Measuring Party Positions and Issue Salience from Media Coverage: Introducing and Cross-Validating New Indicators

Recent studies have started to use media data to measure party positions and issue salience. The aim of this article is to compare and cross-validate this alternative approach with the more commonly used party manifestos, expert judgments and mass surveys. To this purpose, we present two methods to generate indicators of party positions and issue salience from media coverage: the core sentence approach and political claims analysis. Our cross-validation shows that with regard to party positions, indicators derived from the media converge with traditionally used measurements from party manifestos, mass surveys and expert judgments, but that salience indicators measure different underlying constructs. We conclude with a discussion of specific research questions for which media data offer potential advantages over more established methods.

Vertical Clearance Restrictions on Primary Roads and Primary Road Extensions: Standard U.S. Measurements [Vertical Clearance Log], May 1, 2015

The Vertical Clearance Log is prepared for the purpose of providing vertical clearance restrictions by route on the primary road system. This report is used by the Iowa Department of Transportation’s Motor Carrier Services to route oversize vehicles around structures with vertical restrictions too low for the cargo height. The source of the data is the Geographic Information Management System (GIMS) that is managed by the Office of Research & Analytics in the Performance & Technology Division. The data is collected by inspection crews and through the use of LiDAR technology to reflect changes to structures on the primary road system. This log is produced annually.

The attractiveness of the work is affected when production of handcrafted log houses moves indoors

Abstract

Development and Evaluation of a Portable Device for Measuring Curling and Warping in Concrete Pavements, 2016

Portland cement concrete (PCC) pavement undergoes repeated environmental load-related deflection resulting from temperature and moisture variations across pavement depth. This has been recognized as resulting in PCC pavement curling and warping since the mid-1920s. Slab curvature can be further magnified under repeated traffic loads and may ultimately lead to fatigue failures, including top-down and bottom-up transverse, longitudinal, and corner cracking. It is therefore significant to measure the “true” degree of curling and warping in PCC pavements, not only for quality control (QC) and quality assurance (QA) purposes, but also for better understanding of its relationship to long-term pavement performance. Although several approaches and devices—including linear variable differential transducers (LVDTs), digital indicators, and some profilers—have been proposed for measuring curling and warping, their application in the field is subject to cost, inconvenience, and complexity of operation. This research therefore explores developing an economical and simple device for measuring curling and warping in concrete pavements with accuracy comparable to or better than existing methodologies. Technical requirements were identified to establish assessment criteria for development, and field tests were conducted to modify the device to further enhancement. The finalized device is about 12 inches in height and 18 pounds in weight, and its manufacturing cost is just $320. Detailed development procedures and evaluation results for the new curling and warping measuring device are presented and discussed, with a focus on achieving reliable curling and warping measurements in a cost effective manner.

Practical Data Collection: Establishing Methods and Procedures for Measuring Water Clarity and Turbidity of Storm Water Run-Off from Active Major Highway Construction Sites, 2014

In anticipation of regulation involving numeric turbidity limit at highway construction sites, research was done into the most appropriate, affordable methods for surface water monitoring. Measuring sediment concentration in streams may be conducted a number of ways. As part of a project funded by the Iowa Department of Transportation, several testing methods were explored to determine the most affordable, appropriate methods for data collection both in the field and in the lab. The primary purpose of the research was to determine the exchangeability of the acrylic transparency tube for water clarity analysis as compared to the turbidimeter.